This invention relates to construction materials and building construction methods. It provides adhesive formulations suitable for fortifying joints between abutting panels in wall and ceiling assemblies. Methods also provided for using the adhesive formulations with joint seams, joint reinforcement tape, joint reinforcement trim and framing members.
In building construction, different types of claddings are used as panels for forming interior and exterior wall and ceiling surfaces. Typically, the claddings are in the form of boards (also referred to as panels) affixed to framing members such as in balloon framing arrangements known in the art. Examples of claddings include gypsum board faced with paper, fibrous mats (e.g., fiberglass), and the like. These and other types of boards are typically cut to appropriate dimensions and then fastened to framing members, e.g., with screws, nails, or the like to form wall sections formed from multiple boards.
Two side-by-side boards disposed in the same plane will form a joint seam between them on vertical walls and horizontal ceilings. To finish the seam, joint reinforcement tape is embedded in the seam, along with a layer of joint compound under the tape, and multiple coats of joint compound applied over the tape. Some boards meet at an angle such as when forming a corner. Reinforcement bead can be utilized to hide the corner seam and to protect the corner. Reinforcement bead can be directly attached to the board using fasteners, or a layer of joint compound is applied under the trim to adhere the reinforcement bead to the board. The installed reinforcement is then concealed with multiple layers of joint compound applied over the trim. Fasteners used to affix the board to framing members must also be concealed with multiple layers of joint compound applied over them. After the various joint compound applications are dried, the resulting wall surfaces can be sanded and painted to form the desired uniform and aesthetically pleasing appearance.
The level of finishing as described above can vary. For example, with respect to gypsum wallboard, six (6) levels of gypsum board finish are understood in the art, ranging from zero (no treatment at all) to level five (the highest level of finish), as set forth in Gypsum Association document GA-214 and American Society for Testing and Materials (“ASTM”) C840. The level of finish generally corresponds with the number of applications of joint compound to seams, trims, and fasteners. Levels three, four, and five are typically used for occupied spaces within buildings. For single family homes, level 4 is the most common level that is implemented. Level five is less frequently used and usually requires application of a skim coat of joint compound across the entire wall surface.
Conventional approaches for finishing wall assemblies as described above have not been fully satisfactory. The materials conventionally used to finish wall assemblies create significant inefficiencies in the process and also require an advanced level of skill to use effectively. For example, existing joint compounds require three separate coats to be applied to fasteners as well as multiple coats applied to flat seams between boards in the same plane and to corner seams. Each coat must separately dry which introduces significant downtime in the construction process, particularly since the other construction trades ordinarily cannot work inside the building while the wall finishing occurs. Each layer of joint compound can require about a day to dry, and it typically can take about a week to install the gypsum board and finish the flat joints, fasteners, and corner trims for a typical new construction of a home of 2,400 square feet of living space (corresponding to about 10,000 square feet of board).
US Patent Publication US-2014-0083038-A1 describes a joint compound and wall assembly in which a joint compound can be applied in one layer only. This system eliminates the need for applying multiple coats of joint compound and decreases the time needed for wall installation.